With rapid development of a smartphone, functions of the smartphone change quickly. Some detachable function modules, such as a detachable battery module, a detachable photographing module, and other auxiliary function modules, are increasingly widely applied to the smartphone. However, a communication function is still one of the most significant functions of the smartphone. Generally, these auxiliary function modules installed on the smartphone not only bring more functions, but also interfere with communication of the phone, decreasing communication quality of the phone.
In the prior art, the detachable module is usually located at the top of the phone and is mostly made of metallic materials. When the detachable module is added, a top antenna near the detachable module is blocked by the detachable module. Consequently, sensitivity of the top antenna decreases by 6 to 7 decibels, and the phone on which the detachable module is installed has poor communication quality in communication with the outside or even cannot communicate with the outside normally.